1. Field of the Invention
The present invention relates to circuit modules in which an electronic component is mounted on a circuit board.
2. Description of the Related Art
A circuit module having a configuration in which a bump-mounted electronic component, a wire-bonding-mounted electronic component or a surface-mounted electronic component is mounted on a printed board is described in Japanese Unexamined Patent Application Publication No. 2008-235759.
For such circuit modules, it is increasingly the case that electronic components having different characteristics are mounted to replace some electronic components previously mounted on the printed board and the circuit module is shipped as an improved product over the previous circuit module. In the case where new electronic components having improved characteristics are produced, production of previously mounted electronic components is stopped or the firmware of some mounted electronic components is updated, for example, circuit modules are manufactured in which new electronic components having improved characteristics, replacement components for electronic components whose production has stopped or electronic components whose firmware has been updated are mounted as components to replace the electronic components previously mounted on the printed board in the process of manufacturing subsequent circuit modules.
It is often the case that the configurations of the previously mounted electronic components and the replacement mounted electronic components are the same in terms of shape, size, arrangement of pins and so forth, and a printed board having the same design as the printed board on which the previous electronic components were mounted is often used without modifying the design of the printed board since in this way it is possible to eliminate the expense of modifying the design of the printed board.
In such a case, since the characteristics of the mounted electronic components have changed, a circuit module in which an electronic component having improved characteristics or updated firmware is mounted is handled as a different product from the previous circuit module.
However, as described above, for a circuit module that is an improved product having mounted therein electronic components having improved characteristics or updated firmware, these mounted electronic components may have the same shapes, sizes and so forth as the previously mounted electronic components and the same printed board may be used in the circuit module and therefore it is not possible to discriminate from their appearances these circuit modules from the previous circuit modules in which previous components are mounted. Consequently, there has been a problem in that if the previous products become mixed in with one-time improved products, they cannot be discriminated from their appearances and components having different characteristics are shipped out, so as to cause a problem in terms of characteristics at the shipping destination.